[deliverable/linux.git] / arch / i386 / boot / compressed / relocs.c

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <elf.h>
#include <byteswap.h>
#define USE_BSD
#include <endian.h>

#define MAX_SHDRS 100
static Elf32_Ehdr ehdr;
static Elf32_Shdr shdr[MAX_SHDRS];
static Elf32_Sym  *symtab[MAX_SHDRS];
static Elf32_Rel  *reltab[MAX_SHDRS];
static char *strtab[MAX_SHDRS];
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;

/*
 * Following symbols have been audited. There values are constant and do
 * not change if bzImage is loaded at a different physical address than
 * the address for which it has been compiled. Don't warn user about
 * absolute relocations present w.r.t these symbols.
 */
static const char* safe_abs_relocs[] = {
		"__kernel_vsyscall",
		"__kernel_rt_sigreturn",
		"__kernel_sigreturn",
		"SYSENTER_RETURN",
};

static int is_safe_abs_reloc(const char* sym_name)
{
	int i, array_size;

	array_size = sizeof(safe_abs_relocs)/sizeof(char*);

	for(i = 0; i < array_size; i++) {
		if (!strcmp(sym_name, safe_abs_relocs[i]))
			/* Match found */
			return 1;
	}
	if (strncmp(sym_name, "__crc_", 6) == 0)
		return 1;
	return 0;
}

static void die(char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	exit(1);
}

static const char *sym_type(unsigned type)
{
	static const char *type_name[] = {
#define SYM_TYPE(X) [X] = #X
		SYM_TYPE(STT_NOTYPE),
		SYM_TYPE(STT_OBJECT),
		SYM_TYPE(STT_FUNC),
		SYM_TYPE(STT_SECTION),
		SYM_TYPE(STT_FILE),
		SYM_TYPE(STT_COMMON),
		SYM_TYPE(STT_TLS),
#undef SYM_TYPE
	};
	const char *name = "unknown sym type name";
	if (type < sizeof(type_name)/sizeof(type_name[0])) {
		name = type_name[type];
	}
	return name;
}

static const char *sym_bind(unsigned bind)
{
	static const char *bind_name[] = {
#define SYM_BIND(X) [X] = #X
		SYM_BIND(STB_LOCAL),
		SYM_BIND(STB_GLOBAL),
		SYM_BIND(STB_WEAK),
#undef SYM_BIND
	};
	const char *name = "unknown sym bind name";
	if (bind < sizeof(bind_name)/sizeof(bind_name[0])) {
		name = bind_name[bind];
	}
	return name;
}

static const char *sym_visibility(unsigned visibility)
{
	static const char *visibility_name[] = {
#define SYM_VISIBILITY(X) [X] = #X
		SYM_VISIBILITY(STV_DEFAULT),
		SYM_VISIBILITY(STV_INTERNAL),
		SYM_VISIBILITY(STV_HIDDEN),
		SYM_VISIBILITY(STV_PROTECTED),
#undef SYM_VISIBILITY
	};
	const char *name = "unknown sym visibility name";
	if (visibility < sizeof(visibility_name)/sizeof(visibility_name[0])) {
		name = visibility_name[visibility];
	}
	return name;
}

static const char *rel_type(unsigned type)
{
	static const char *type_name[] = {
#define REL_TYPE(X) [X] = #X
		REL_TYPE(R_386_NONE),
		REL_TYPE(R_386_32),
		REL_TYPE(R_386_PC32),
		REL_TYPE(R_386_GOT32),
		REL_TYPE(R_386_PLT32),
		REL_TYPE(R_386_COPY),
		REL_TYPE(R_386_GLOB_DAT),
		REL_TYPE(R_386_JMP_SLOT),
		REL_TYPE(R_386_RELATIVE),
		REL_TYPE(R_386_GOTOFF),
		REL_TYPE(R_386_GOTPC),
#undef REL_TYPE
	};
	const char *name = "unknown type rel type name";
	if (type < sizeof(type_name)/sizeof(type_name[0])) {
		name = type_name[type];
	}
	return name;
}

static const char *sec_name(unsigned shndx)
{
	const char *sec_strtab;
	const char *name;
	sec_strtab = strtab[ehdr.e_shstrndx];
	name = "<noname>";
	if (shndx < ehdr.e_shnum) {
		name = sec_strtab + shdr[shndx].sh_name;
	}
	else if (shndx == SHN_ABS) {
		name = "ABSOLUTE";
	}
	else if (shndx == SHN_COMMON) {
		name = "COMMON";
	}
	return name;
}

static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
{
	const char *name;
	name = "<noname>";
	if (sym->st_name) {
		name = sym_strtab + sym->st_name;
	}
	else {
		name = sec_name(shdr[sym->st_shndx].sh_name);
	}
	return name;
}


#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
#endif
#if BYTE_ORDER == BIG_ENDIAN
#define le16_to_cpu(val) bswap_16(val)
#define le32_to_cpu(val) bswap_32(val)
#endif

static uint16_t elf16_to_cpu(uint16_t val)
{
	return le16_to_cpu(val);
}

static uint32_t elf32_to_cpu(uint32_t val)
{
	return le32_to_cpu(val);
}

static void read_ehdr(FILE *fp)
{
	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
		die("Cannot read ELF header: %s\n",
			strerror(errno));
	}
	if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
		die("No ELF magic\n");
	}
	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
		die("Not a 32 bit executable\n");
	}
	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
		die("Not a LSB ELF executable\n");
	}
	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
		die("Unknown ELF version\n");
	}
	/* Convert the fields to native endian */
	ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
	ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
	ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
	ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
	ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
	ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
	ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
	ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
	ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
	ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
	ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);

	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
		die("Unsupported ELF header type\n");
	}
	if (ehdr.e_machine != EM_386) {
		die("Not for x86\n");
	}
	if (ehdr.e_version != EV_CURRENT) {
		die("Unknown ELF version\n");
	}
	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
		die("Bad Elf header size\n");
	}
	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
		die("Bad program header entry\n");
	}
	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
		die("Bad section header entry\n");
	}
	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
		die("String table index out of bounds\n");
	}
}

static void read_shdrs(FILE *fp)
{
	int i;
	if (ehdr.e_shnum > MAX_SHDRS) {
		die("%d section headers supported: %d\n",
			ehdr.e_shnum, MAX_SHDRS);
	}
	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
		die("Seek to %d failed: %s\n",
			ehdr.e_shoff, strerror(errno));
	}
	if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
		die("Cannot read ELF section headers: %s\n",
			strerror(errno));
	}
	for(i = 0; i < ehdr.e_shnum; i++) {
		shdr[i].sh_name      = elf32_to_cpu(shdr[i].sh_name);
		shdr[i].sh_type      = elf32_to_cpu(shdr[i].sh_type);
		shdr[i].sh_flags     = elf32_to_cpu(shdr[i].sh_flags);
		shdr[i].sh_addr      = elf32_to_cpu(shdr[i].sh_addr);
		shdr[i].sh_offset    = elf32_to_cpu(shdr[i].sh_offset);
		shdr[i].sh_size      = elf32_to_cpu(shdr[i].sh_size);
		shdr[i].sh_link      = elf32_to_cpu(shdr[i].sh_link);
		shdr[i].sh_info      = elf32_to_cpu(shdr[i].sh_info);
		shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
		shdr[i].sh_entsize   = elf32_to_cpu(shdr[i].sh_entsize);
	}

}

static void read_strtabs(FILE *fp)
{
	int i;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_STRTAB) {
			continue;
		}
		strtab[i] = malloc(shdr[i].sh_size);
		if (!strtab[i]) {
			die("malloc of %d bytes for strtab failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
	}
}

static void read_symtabs(FILE *fp)
{
	int i,j;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_SYMTAB) {
			continue;
		}
		symtab[i] = malloc(shdr[i].sh_size);
		if (!symtab[i]) {
			die("malloc of %d bytes for symtab failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
			symtab[i][j].st_name  = elf32_to_cpu(symtab[i][j].st_name);
			symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
			symtab[i][j].st_size  = elf32_to_cpu(symtab[i][j].st_size);
			symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
		}
	}
}


static void read_relocs(FILE *fp)
{
	int i,j;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		reltab[i] = malloc(shdr[i].sh_size);
		if (!reltab[i]) {
			die("malloc of %d bytes for relocs failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
			reltab[i][j].r_info   = elf32_to_cpu(reltab[i][j].r_info);
		}
	}
}


static void print_absolute_symbols(void)
{
	int i;
	printf("Absolute symbols\n");
	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
	for(i = 0; i < ehdr.e_shnum; i++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		int j;
		if (shdr[i].sh_type != SHT_SYMTAB) {
			continue;
		}
		sh_symtab = symtab[i];
		sym_strtab = strtab[shdr[i].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
			Elf32_Sym *sym;
			const char *name;
			sym = &symtab[i][j];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}
			printf("%5d %08x %5d %10s %10s %12s %s\n",
				j, sym->st_value, sym->st_size,
				sym_type(ELF32_ST_TYPE(sym->st_info)),
				sym_bind(ELF32_ST_BIND(sym->st_info)),
				sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
				name);
		}
	}
	printf("\n");
}

static void print_absolute_relocs(void)
{
	int i, printed = 0;

	for(i = 0; i < ehdr.e_shnum; i++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		unsigned sec_applies, sec_symtab;
		int j;
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = shdr[i].sh_link;
		sec_applies = shdr[i].sh_info;
		if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = symtab[sec_symtab];
		sym_strtab = strtab[shdr[sec_symtab].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			const char *name;
			rel = &reltab[i][j];
			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}

			/* Absolute symbols are not relocated if bzImage is
			 * loaded at a non-compiled address. Display a warning
			 * to user at compile time about the absolute
			 * relocations present.
			 *
			 * User need to audit the code to make sure
			 * some symbols which should have been section
			 * relative have not become absolute because of some
			 * linker optimization or wrong programming usage.
			 *
			 * Before warning check if this absolute symbol
			 * relocation is harmless.
			 */
			if (is_safe_abs_reloc(name))
				continue;

			if (!printed) {
				printf("WARNING: Absolute relocations"
					" present\n");
				printf("Offset     Info     Type     Sym.Value "
					"Sym.Name\n");
				printed = 1;
			}

			printf("%08x %08x %10s %08x  %s\n",
				rel->r_offset,
				rel->r_info,
				rel_type(ELF32_R_TYPE(rel->r_info)),
				sym->st_value,
				name);
		}
	}

	if (printed)
		printf("\n");
}

static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
{
	int i;
	/* Walk through the relocations */
	for(i = 0; i < ehdr.e_shnum; i++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		unsigned sec_applies, sec_symtab;
		int j;
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = shdr[i].sh_link;
		sec_applies = shdr[i].sh_info;
		if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = symtab[sec_symtab];
		sym_strtab = strtab[shdr[sec_symtab].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			unsigned r_type;
			rel = &reltab[i][j];
			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
			r_type = ELF32_R_TYPE(rel->r_info);
			/* Don't visit relocations to absolute symbols */
			if (sym->st_shndx == SHN_ABS) {
				continue;
			}
			if (r_type == R_386_PC32) {
				/* PC relative relocations don't need to be adjusted */
			}
			else if (r_type == R_386_32) {
				/* Visit relocations that need to be adjusted */
				visit(rel, sym);
			}
			else {
				die("Unsupported relocation type: %d\n", r_type);
			}
		}
	}
}

static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
{
	reloc_count += 1;
}

static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
{
	/* Remember the address that needs to be adjusted. */
	relocs[reloc_idx++] = rel->r_offset;
}

static int cmp_relocs(const void *va, const void *vb)
{
	const unsigned long *a, *b;
	a = va; b = vb;
	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
}

static void emit_relocs(int as_text)
{
	int i;
	/* Count how many relocations I have and allocate space for them. */
	reloc_count = 0;
	walk_relocs(count_reloc);
	relocs = malloc(reloc_count * sizeof(relocs[0]));
	if (!relocs) {
		die("malloc of %d entries for relocs failed\n",
			reloc_count);
	}
	/* Collect up the relocations */
	reloc_idx = 0;
	walk_relocs(collect_reloc);

	/* Order the relocations for more efficient processing */
	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);

	/* Print the relocations */
	if (as_text) {
		/* Print the relocations in a form suitable that
		 * gas will like.
		 */
		printf(".section \".data.reloc\",\"a\"\n");
		printf(".balign 4\n");
		for(i = 0; i < reloc_count; i++) {
			printf("\t .long 0x%08lx\n", relocs[i]);
		}
		printf("\n");
	}
	else {
		unsigned char buf[4];
		buf[0] = buf[1] = buf[2] = buf[3] = 0;
		/* Print a stop */
		printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
		/* Now print each relocation */
		for(i = 0; i < reloc_count; i++) {
			buf[0] = (relocs[i] >>  0) & 0xff;
			buf[1] = (relocs[i] >>  8) & 0xff;
			buf[2] = (relocs[i] >> 16) & 0xff;
			buf[3] = (relocs[i] >> 24) & 0xff;
			printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
		}
	}
}

static void usage(void)
{
	die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
}

int main(int argc, char **argv)
{
	int show_absolute_syms, show_absolute_relocs;
	int as_text;
	const char *fname;
	FILE *fp;
	int i;

	show_absolute_syms = 0;
	show_absolute_relocs = 0;
	as_text = 0;
	fname = NULL;
	for(i = 1; i < argc; i++) {
		char *arg = argv[i];
		if (*arg == '-') {
			if (strcmp(argv[1], "--abs-syms") == 0) {
				show_absolute_syms = 1;
				continue;
			}

			if (strcmp(argv[1], "--abs-relocs") == 0) {
				show_absolute_relocs = 1;
				continue;
			}
			else if (strcmp(argv[1], "--text") == 0) {
				as_text = 1;
				continue;
			}
		}
		else if (!fname) {
			fname = arg;
			continue;
		}
		usage();
	}
	if (!fname) {
		usage();
	}
	fp = fopen(fname, "r");
	if (!fp) {
		die("Cannot open %s: %s\n",
			fname, strerror(errno));
	}
	read_ehdr(fp);
	read_shdrs(fp);
	read_strtabs(fp);
	read_symtabs(fp);
	read_relocs(fp);
	if (show_absolute_syms) {
		print_absolute_symbols();
		return 0;
	}
	if (show_absolute_relocs) {
		print_absolute_relocs();
		return 0;
	}
	emit_relocs(as_text);
	return 0;
}
Commit	Line	Data
968de4f0 EB	1	#include <stdio.h>
	2	#include <stdarg.h>
	3	#include <stdlib.h>
	4	#include <stdint.h>
	5	#include <string.h>
	6	#include <errno.h>
	7	#include <unistd.h>
	8	#include <elf.h>
	9	#include <byteswap.h>
	10	#define USE_BSD
	11	#include <endian.h>
	12
	13	#define MAX_SHDRS 100
	14	static Elf32_Ehdr ehdr;
	15	static Elf32_Shdr shdr[MAX_SHDRS];
	16	static Elf32_Sym *symtab[MAX_SHDRS];
	17	static Elf32_Rel *reltab[MAX_SHDRS];
	18	static char *strtab[MAX_SHDRS];
	19	static unsigned long reloc_count, reloc_idx;
	20	static unsigned long *relocs;
	21
6a044b3a VG	22	/*
	23	* Following symbols have been audited. There values are constant and do
	24	* not change if bzImage is loaded at a different physical address than
	25	* the address for which it has been compiled. Don't warn user about
	26	* absolute relocations present w.r.t these symbols.
	27	*/
	28	static const char* safe_abs_relocs[] = {
	29	"__kernel_vsyscall",
	30	"__kernel_rt_sigreturn",
	31	"__kernel_sigreturn",
	32	"SYSENTER_RETURN",
	33	};
	34
	35	static int is_safe_abs_reloc(const char* sym_name)
	36	{
	37	int i, array_size;
	38
	39	array_size = sizeof(safe_abs_relocs)/sizeof(char*);
	40
	41	for(i = 0; i < array_size; i++) {
	42	if (!strcmp(sym_name, safe_abs_relocs[i]))
	43	/* Match found */
	44	return 1;
	45	}
2a3d4f1f AV	46	if (strncmp(sym_name, "__crc_", 6) == 0)
2a3d4f1f AV	47	return 1;
6a044b3a VG	48	return 0;
	49	}
	50
968de4f0 EB	51	static void die(char *fmt, ...)
	52	{
	53	va_list ap;
	54	va_start(ap, fmt);
	55	vfprintf(stderr, fmt, ap);
	56	va_end(ap);
	57	exit(1);
	58	}
	59
	60	static const char *sym_type(unsigned type)
	61	{
	62	static const char *type_name[] = {
	63	#define SYM_TYPE(X) [X] = #X
	64	SYM_TYPE(STT_NOTYPE),
	65	SYM_TYPE(STT_OBJECT),
	66	SYM_TYPE(STT_FUNC),
	67	SYM_TYPE(STT_SECTION),
	68	SYM_TYPE(STT_FILE),
	69	SYM_TYPE(STT_COMMON),
	70	SYM_TYPE(STT_TLS),
	71	#undef SYM_TYPE
	72	};
	73	const char *name = "unknown sym type name";
	74	if (type < sizeof(type_name)/sizeof(type_name[0])) {
	75	name = type_name[type];
	76	}
	77	return name;
	78	}
	79
	80	static const char *sym_bind(unsigned bind)
	81	{
	82	static const char *bind_name[] = {
	83	#define SYM_BIND(X) [X] = #X
	84	SYM_BIND(STB_LOCAL),
	85	SYM_BIND(STB_GLOBAL),
	86	SYM_BIND(STB_WEAK),
	87	#undef SYM_BIND
	88	};
	89	const char *name = "unknown sym bind name";
	90	if (bind < sizeof(bind_name)/sizeof(bind_name[0])) {
	91	name = bind_name[bind];
	92	}
	93	return name;
	94	}
	95
	96	static const char *sym_visibility(unsigned visibility)
	97	{
	98	static const char *visibility_name[] = {
	99	#define SYM_VISIBILITY(X) [X] = #X
	100	SYM_VISIBILITY(STV_DEFAULT),
	101	SYM_VISIBILITY(STV_INTERNAL),
	102	SYM_VISIBILITY(STV_HIDDEN),
	103	SYM_VISIBILITY(STV_PROTECTED),
	104	#undef SYM_VISIBILITY
	105	};
	106	const char *name = "unknown sym visibility name";
	107	if (visibility < sizeof(visibility_name)/sizeof(visibility_name[0])) {
	108	name = visibility_name[visibility];
	109	}
	110	return name;
	111	}
	112
	113	static const char *rel_type(unsigned type)
	114	{
115	static const char *type_name[] = {
116	#define REL_TYPE(X) [X] = #X
117	REL_TYPE(R_386_NONE),
118	REL_TYPE(R_386_32),
119	REL_TYPE(R_386_PC32),
120	REL_TYPE(R_386_GOT32),
121	REL_TYPE(R_386_PLT32),
122	REL_TYPE(R_386_COPY),
123	REL_TYPE(R_386_GLOB_DAT),
124	REL_TYPE(R_386_JMP_SLOT),
125	REL_TYPE(R_386_RELATIVE),
126	REL_TYPE(R_386_GOTOFF),
127	REL_TYPE(R_386_GOTPC),
128	#undef REL_TYPE
129	};
130	const char *name = "unknown type rel type name";
131	if (type < sizeof(type_name)/sizeof(type_name[0])) {
132	name = type_name[type];
133	}
134	return name;
135	}
136
137	static const char *sec_name(unsigned shndx)
138	{
139	const char *sec_strtab;
140	const char *name;
141	sec_strtab = strtab[ehdr.e_shstrndx];
142	name = "<noname>";
143	if (shndx < ehdr.e_shnum) {
144	name = sec_strtab + shdr[shndx].sh_name;
145	}
146	else if (shndx == SHN_ABS) {
147	name = "ABSOLUTE";
148	}
149	else if (shndx == SHN_COMMON) {
150	name = "COMMON";
151	}
152	return name;
153	}
154
155	static const char sym_name(const char sym_strtab, Elf32_Sym *sym)
156	{
157	const char *name;
158	name = "<noname>";
159	if (sym->st_name) {
160	name = sym_strtab + sym->st_name;
161	}
162	else {
163	name = sec_name(shdr[sym->st_shndx].sh_name);
164	}
165	return name;
166	}
167
168
169
170	#if BYTE_ORDER == LITTLE_ENDIAN
171	#define le16_to_cpu(val) (val)
172	#define le32_to_cpu(val) (val)
173	#endif
174	#if BYTE_ORDER == BIG_ENDIAN
175	#define le16_to_cpu(val) bswap_16(val)
176	#define le32_to_cpu(val) bswap_32(val)
177	#endif
178
179	static uint16_t elf16_to_cpu(uint16_t val)
180	{
181	return le16_to_cpu(val);
182	}
183
184	static uint32_t elf32_to_cpu(uint32_t val)
185	{
186	return le32_to_cpu(val);
187	}
188
189	static void read_ehdr(FILE *fp)
190	{
191	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
192	die("Cannot read ELF header: %s\n",
193	strerror(errno));
194	}
195	if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
196	die("No ELF magic\n");
197	}
198	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
199	die("Not a 32 bit executable\n");
200	}
201	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
202	die("Not a LSB ELF executable\n");
203	}
204	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
205	die("Unknown ELF version\n");
206	}
207	/* Convert the fields to native endian */
208	ehdr.e_type = elf16_to_cpu(ehdr.e_type);
209	ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
210	ehdr.e_version = elf32_to_cpu(ehdr.e_version);
211	ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
212	ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
213	ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
214	ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
215	ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
216	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
217	ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
218	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
219	ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
220	ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
221
222	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
223	die("Unsupported ELF header type\n");
224	}
225	if (ehdr.e_machine != EM_386) {
226	die("Not for x86\n");
227	}
228	if (ehdr.e_version != EV_CURRENT) {
229	die("Unknown ELF version\n");
230	}
231	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
232	die("Bad Elf header size\n");
233	}
234	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
235	die("Bad program header entry\n");
236	}
237	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
238	die("Bad section header entry\n");
239	}
240	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
241	die("String table index out of bounds\n");
242	}
243	}
244
245	static void read_shdrs(FILE *fp)
246	{
247	int i;
248	if (ehdr.e_shnum > MAX_SHDRS) {
249	die("%d section headers supported: %d\n",
250	ehdr.e_shnum, MAX_SHDRS);
251	}
252	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
253	die("Seek to %d failed: %s\n",
254	ehdr.e_shoff, strerror(errno));
255	}
256	if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
257	die("Cannot read ELF section headers: %s\n",
258	strerror(errno));
259	}
260	for(i = 0; i < ehdr.e_shnum; i++) {
261	shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
262	shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
263	shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
264	shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
265	shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
266	shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
267	shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
268	shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
269	shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
270	shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
271	}
272
273	}
274
275	static void read_strtabs(FILE *fp)
276	{
277	int i;
278	for(i = 0; i < ehdr.e_shnum; i++) {
279	if (shdr[i].sh_type != SHT_STRTAB) {
280	continue;
281	}
282	strtab[i] = malloc(shdr[i].sh_size);
283	if (!strtab[i]) {
284	die("malloc of %d bytes for strtab failed\n",
285	shdr[i].sh_size);
286	}
287	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
288	die("Seek to %d failed: %s\n",
289	shdr[i].sh_offset, strerror(errno));
290	}
291	if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
292	die("Cannot read symbol table: %s\n",
293	strerror(errno));
294	}
295	}
296	}
297
298	static void read_symtabs(FILE *fp)
299	{
300	int i,j;
301	for(i = 0; i < ehdr.e_shnum; i++) {
302	if (shdr[i].sh_type != SHT_SYMTAB) {
303	continue;
304	}
305	symtab[i] = malloc(shdr[i].sh_size);
306	if (!symtab[i]) {
307	die("malloc of %d bytes for symtab failed\n",
308	shdr[i].sh_size);
309	}
310	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
311	die("Seek to %d failed: %s\n",
312	shdr[i].sh_offset, strerror(errno));
313	}
314	if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
315	die("Cannot read symbol table: %s\n",
316	strerror(errno));
317	}
318	for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
319	symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
320	symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
321	symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
322	symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
323	}
324	}
325	}
326
327
328	static void read_relocs(FILE *fp)
329	{
330	int i,j;
331	for(i = 0; i < ehdr.e_shnum; i++) {
332	if (shdr[i].sh_type != SHT_REL) {
333	continue;
334	}
335	reltab[i] = malloc(shdr[i].sh_size);
336	if (!reltab[i]) {
337	die("malloc of %d bytes for relocs failed\n",
338	shdr[i].sh_size);
339	}
340	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
341	die("Seek to %d failed: %s\n",
342	shdr[i].sh_offset, strerror(errno));
343	}
344	if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
345	die("Cannot read symbol table: %s\n",
346	strerror(errno));
347	}
348	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
349	reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
350	reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
351	}
352	}
353	}
354
355
356	static void print_absolute_symbols(void)
357	{
358	int i;
359	printf("Absolute symbols\n");
360	printf(" Num: Value Size Type Bind Visibility Name\n");
361	for(i = 0; i < ehdr.e_shnum; i++) {
362	char *sym_strtab;
363	Elf32_Sym *sh_symtab;
364	int j;
365	if (shdr[i].sh_type != SHT_SYMTAB) {
366	continue;
367	}
368	sh_symtab = symtab[i];
369	sym_strtab = strtab[shdr[i].sh_link];
370	for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
371	Elf32_Sym *sym;
372	const char *name;
373	sym = &symtab[i][j];
374	name = sym_name(sym_strtab, sym);
375	if (sym->st_shndx != SHN_ABS) {
376	continue;
377	}
378	printf("%5d %08x %5d %10s %10s %12s %s\n",
379	j, sym->st_value, sym->st_size,
380	sym_type(ELF32_ST_TYPE(sym->st_info)),
381	sym_bind(ELF32_ST_BIND(sym->st_info)),
382	sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
383	name);
384	}
385	}
386	printf("\n");
387	}
388
389	static void print_absolute_relocs(void)
390	{
6a044b3a VG	391	int i, printed = 0;
6a044b3a VG	392
968de4f0 EB	393	for(i = 0; i < ehdr.e_shnum; i++) {
	394	char *sym_strtab;
	395	Elf32_Sym *sh_symtab;
	396	unsigned sec_applies, sec_symtab;
	397	int j;
	398	if (shdr[i].sh_type != SHT_REL) {
	399	continue;
	400	}
	401	sec_symtab = shdr[i].sh_link;
	402	sec_applies = shdr[i].sh_info;
	403	if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
	404	continue;
	405	}
	406	sh_symtab = symtab[sec_symtab];
	407	sym_strtab = strtab[shdr[sec_symtab].sh_link];
	408	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
	409	Elf32_Rel *rel;
	410	Elf32_Sym *sym;
	411	const char *name;
	412	rel = &reltab[i][j];
	413	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
	414	name = sym_name(sym_strtab, sym);
	415	if (sym->st_shndx != SHN_ABS) {
	416	continue;
	417	}
6a044b3a VG	418
	419	/* Absolute symbols are not relocated if bzImage is
	420	* loaded at a non-compiled address. Display a warning
	421	* to user at compile time about the absolute
	422	* relocations present.
	423	*
	424	* User need to audit the code to make sure
	425	* some symbols which should have been section
	426	* relative have not become absolute because of some
	427	* linker optimization or wrong programming usage.
	428	*
	429	* Before warning check if this absolute symbol
	430	* relocation is harmless.
	431	*/
	432	if (is_safe_abs_reloc(name))
	433	continue;
	434
	435	if (!printed) {
	436	printf("WARNING: Absolute relocations"
	437	" present\n");
	438	printf("Offset Info Type Sym.Value "
	439	"Sym.Name\n");
	440	printed = 1;
	441	}
	442
968de4f0 EB	443	printf("%08x %08x %10s %08x %s\n",
	444	rel->r_offset,
	445	rel->r_info,
	446	rel_type(ELF32_R_TYPE(rel->r_info)),
	447	sym->st_value,
	448	name);
	449	}
	450	}
6a044b3a VG	451
	452	if (printed)
	453	printf("\n");
968de4f0 EB	454	}
	455
	456	static void walk_relocs(void (visit)(Elf32_Rel rel, Elf32_Sym *sym))
	457	{
	458	int i;
	459	/* Walk through the relocations */
	460	for(i = 0; i < ehdr.e_shnum; i++) {
	461	char *sym_strtab;
	462	Elf32_Sym *sh_symtab;
	463	unsigned sec_applies, sec_symtab;
	464	int j;
	465	if (shdr[i].sh_type != SHT_REL) {
	466	continue;
	467	}
	468	sec_symtab = shdr[i].sh_link;
	469	sec_applies = shdr[i].sh_info;
	470	if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
	471	continue;
	472	}
	473	sh_symtab = symtab[sec_symtab];
	474	sym_strtab = strtab[shdr[sec_symtab].sh_link];
	475	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
	476	Elf32_Rel *rel;
	477	Elf32_Sym *sym;
	478	unsigned r_type;
	479	rel = &reltab[i][j];
	480	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
	481	r_type = ELF32_R_TYPE(rel->r_info);
	482	/* Don't visit relocations to absolute symbols */
	483	if (sym->st_shndx == SHN_ABS) {
	484	continue;
	485	}
	486	if (r_type == R_386_PC32) {
	487	/* PC relative relocations don't need to be adjusted */
	488	}
	489	else if (r_type == R_386_32) {
	490	/* Visit relocations that need to be adjusted */
	491	visit(rel, sym);
	492	}
	493	else {
	494	die("Unsupported relocation type: %d\n", r_type);
	495	}
	496	}
	497	}
	498	}
	499
	500	static void count_reloc(Elf32_Rel rel, Elf32_Sym sym)
	501	{
	502	reloc_count += 1;
	503	}
	504
	505	static void collect_reloc(Elf32_Rel rel, Elf32_Sym sym)
	506	{
	507	/* Remember the address that needs to be adjusted. */
	508	relocs[reloc_idx++] = rel->r_offset;
	509	}
	510
	511	static int cmp_relocs(const void va, const void vb)
	512	{
	513	const unsigned long a, b;
	514	a = va; b = vb;
	515	return (a == b)? 0 : (a > b)? 1 : -1;
	516	}
	517
518	static void emit_relocs(int as_text)
519	{
520	int i;
521	/* Count how many relocations I have and allocate space for them. */
522	reloc_count = 0;
523	walk_relocs(count_reloc);
524	relocs = malloc(reloc_count * sizeof(relocs[0]));
525	if (!relocs) {
526	die("malloc of %d entries for relocs failed\n",
527	reloc_count);
528	}
529	/* Collect up the relocations */
530	reloc_idx = 0;
531	walk_relocs(collect_reloc);
532
533	/* Order the relocations for more efficient processing */
534	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
535
536	/* Print the relocations */
537	if (as_text) {
538	/* Print the relocations in a form suitable that
539	* gas will like.
540	*/
541	printf(".section \".data.reloc\",\"a\"\n");
542	printf(".balign 4\n");
543	for(i = 0; i < reloc_count; i++) {
544	printf("\t .long 0x%08lx\n", relocs[i]);
545	}
546	printf("\n");
547	}
548	else {
549	unsigned char buf[4];
550	buf[0] = buf[1] = buf[2] = buf[3] = 0;
551	/* Print a stop */
552	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
553	/* Now print each relocation */
554	for(i = 0; i < reloc_count; i++) {
555	buf[0] = (relocs[i] >> 0) & 0xff;
556	buf[1] = (relocs[i] >> 8) & 0xff;
557	buf[2] = (relocs[i] >> 16) & 0xff;
558	buf[3] = (relocs[i] >> 24) & 0xff;
559	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
560	}
561	}
562	}
563
564	static void usage(void)
565	{
6a044b3a	566	die("relocs [--abs-syms \|--abs-relocs \| --text] vmlinux\n");
968de4f0 EB	567	}
	568
	569	int main(int argc, char **argv)
	570	{
6a044b3a	571	int show_absolute_syms, show_absolute_relocs;
968de4f0 EB	572	int as_text;
	573	const char *fname;
	574	FILE *fp;
	575	int i;
	576
6a044b3a VG	577	show_absolute_syms = 0;
6a044b3a VG	578	show_absolute_relocs = 0;
968de4f0 EB	579	as_text = 0;
	580	fname = NULL;
	581	for(i = 1; i < argc; i++) {
	582	char *arg = argv[i];
	583	if (*arg == '-') {
6a044b3a VG	584	if (strcmp(argv[1], "--abs-syms") == 0) {
	585	show_absolute_syms = 1;
	586	continue;
	587	}
	588
	589	if (strcmp(argv[1], "--abs-relocs") == 0) {
	590	show_absolute_relocs = 1;
968de4f0 EB	591	continue;
	592	}
	593	else if (strcmp(argv[1], "--text") == 0) {
	594	as_text = 1;
	595	continue;
	596	}
	597	}
	598	else if (!fname) {
	599	fname = arg;
	600	continue;
	601	}
	602	usage();
	603	}
	604	if (!fname) {
	605	usage();
	606	}
	607	fp = fopen(fname, "r");
	608	if (!fp) {
	609	die("Cannot open %s: %s\n",
	610	fname, strerror(errno));
	611	}
	612	read_ehdr(fp);
	613	read_shdrs(fp);
	614	read_strtabs(fp);
	615	read_symtabs(fp);
	616	read_relocs(fp);
6a044b3a	617	if (show_absolute_syms) {
968de4f0	618	print_absolute_symbols();
6a044b3a VG	619	return 0;
	620	}
	621	if (show_absolute_relocs) {
968de4f0 EB	622	print_absolute_relocs();
	623	return 0;
	624	}
	625	emit_relocs(as_text);
	626	return 0;
	627	}